Maybe implement a "Star Abuse System" that would check for a number of Star/unstar events. possibly 3-5 sets on the same post, or that many star/unstar events within a time period, say for example 5 diffrent star/unstar events within 5 min.
I can see the use for undoing them by accident, or even for a temp highlight, but without wanting it on the wall.
This would prevent the rapid star/unstar behavior, but keep it for the "accidental" or other use.